Generalized beta 2-microglobulin deposition. A preamyloidosis disorder?

Generalized beta 2-microglobulin deposition in the tissues of a 64-year-old man with idiopathic end-stage renal disease was determined post mortem by the use of immunoperoxidase and radial immunodiffusion techniques. He developed progressive organ failure secondary to beta 2-microglobulin deposition, requiring dialysis for the last two years of his life. His immediate cause of death was severe bronchopneumonia. The extensive tissular deposits were shown to be congophilic but not birefringent by alkaline Congo red stains. Immunochemical studies showed that the deposits were beta 2-microglobulin-positive but AA amyloid-, P-component-, prealbumin-, and kappa and lambda light chain-negative. We suggest that this patient had a primary beta 2-microglobulin dyscrasia in which beta 2-microglobulin deposited in tissues but did not undergo complete amyloidogenic change.